[Effects of Activated Carbon on the Fate of Antibiotic Resistance Genes During Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste].

The organic fraction of municipal solid waste (OFMSW) has become one of the sources and reservoirs of antibiotic resistance genes (ARGs). It is essential to explore the fate of ARGs during biological treatment of OFMSW. Therefore, the changes in several types of ARGs and integron genes during anaerobic digestion of the OFMSW were analyzed by quantitative PCR. Furthermore, the effects of different particle sizes of activated carbon on the behaviors of the target genes and the potential microbial mechanisms of ARGs dynamics were investigated. The results showed that the total ARGs in the initial system were reduced after anaerobic digestion with or without the presence of activated carbon. The removal rate of the absolute abundance of total ARGs was 29.95%-63.40%. In the final system of anaerobic digestion of the OFMSW, the abundance of total ARGs in powdered activated carbon (PAC) groups was significantly higher than that in the control group (P<0.05). The supplementation of PAC inhibited the reduction of ARGs, and the supplementation of granular activated carbon had no significant effect on the change in ARGs. The potential host bacteria of ARGs were mainly Clostridia, Bacteroidia, and Synergistia during anaerobic digestion. The enrichment of host bacteria caused by PAC addition was the main reason for the increase in the target genes. Moreover, Clostridia might have been the main driving factor for the growth and decline of ARGs. These results will help us to understand the dissemination of ARGs and the impacts of activated carbon addition on ARGs during anaerobic digestion of the OFMSW.

[Distribution of Multidrug-Resistant Bacteria and Antibiotic-Resistant Genes in Livestock Manures].

In the present study, techniques for microbial culture enumeration, 16S rDNA gene sequencing for bacterial identification, high-throughput sequencing for the multidrug-resistant bacteria (MRB) communities, and high-throughput quantitative PCR detection for the prevalence and abundance of antibiotic resistance genes (ARGs) were conducted to investigate the distribution characteristics of MRB and ARGs in chicken and swine manures. The results showed that the rates of MRB that were resistant to tetracycline, ciprofloxacin, and gentamycin simultaneously were from 7.96% to 12.40% for the different manure samples. The dominant genera of cultivable MRB were Escherichia, Acinetobacter, and Proteus, both in the chicken and swine manures. High-throughput quantitative PCR results indicated that, compared to the antibiotic free swine manure, the total enrichment of ARGs increased by 1.96×104-1.54×105 times that in the swine manure samples, with different antibiotics following the sequence of tetracyclines > ß-lactams > MLSB (macrolide, lincosamide, and streptogramin B) > aminoglycosides > FCA (fluoroquinolone, quinolone, florfenicol, chloramphenicol, and amphenicol) > sulfonamides > vancomycins.

Expression of programmed death-1 and its ligands in the liver of biliary atresia.

BACKGROUND: An aberrant immune response is the predominant pathogenetic factor in biliary atresia (BA). Programmed death-1 (PD-1) and its two ligands, programmed death ligand-1 and programmed death ligand-2 (PD-L1 and PD-L2, respectively) play an important inhibitory role in immune reactions. We aimed to illustrate the expression of these molecules in BA. METHODS: Liver specimens were obtained from infants with BA during the Kasai procedure (early BA) and liver transplantation (late BA). Intrahepatic expression of PD- 1, PD-L1, and PD-L2 were examined by immunostaining and compared with that in patients with neonatal hepatitis syndrome and normal controls. The correlation between the expression levels of these molecules in the liver and clinicopathological parameters was analyzed for each group. RESULTS: Enhanced expression of PD-1 and its ligands occurred in the livers with early BA. In the BA-affected livers, PD-1 was correlated with the degree of peri-biliary inflammation, while PD-L2 was linked more directly with portal fibrosis. None of the three molecules was correlated with the prognosis of the Kasai procedure in patients with early BA. CONCLUSIONS: Only PD-1 and PD-L1 are involved in the immune reactions of early BA. Elucidation of the detailed role of PD-L2 in BA requires further research.